If you want to use that iPhone for navigation in your car you're gonna need a car kit because just like your private parts in public, your navigation device needs to be "touched infrequently".

Key features of the car kit are securing mounting in portrait or landscape mode with a simple twist and lock motion, enhanced GPS performance thanks to a built-in receiver and a built-in speaker and microphone for voice navigation and handsfree calling. The dock even charges your iPhone on the go.

The car kit has an RRP of $200 and is available from Harvery Norman, JB Hi-fi and Dick Smith.
The TomTom app for iPhone (v 1.2), including map of New Zealand, is available for $120 from the Apple App Store.